As I'm back here just now - I suppose what I'm going for is more of a Vib Ribbon (or... Monster Rancher) approach, where the music is used as the seed and for the background music for the level. I'm getting similar comments on TIGSource, though, about having some connection to the music - so what I might do is have a visual indicator of that at some level (pulsing to the beat as far as I can do so, or something) to make the connection clear to the player at some level.